When taking investments into account, Wyoming's Teton County -- home to Jackson Hole -- takes the top spot.

Teton County only ranks 195th among counties in terms of average wage and salary income ($47,715) but it was No. 1 in terms of average adjusted gross income ($296,778), dividend income ($32,793) and interest ($8,604).

The icing on the cake for Teton County residents is that they got to keep much more of that income than they would in many other places, since the state of Wyoming doesn't tax income, whether derived from a paycheck or investments.

By contrast, the county with the lowest reported average AGI in the country was Gooding County, Idaho ($15,379).

Among states overall, Connecticut secured the top spot in terms of AGI ($91,417) while Mississippi came in last ($44,972).